Resolving ORA-01034 and ORA-27101 errors when connecting to oracle 11g

Resolving oracle 11g reporting ORA-01034 and ORA-27101 errors the database version I locally installed is ORACLE 11G R2, when connecting with plsql, the following ora-12514 error is reported:
However, when using sqlplus in cmd to connect a user already created, the following error is reported:
ORA-01034-Oracle not availableORA-27101-shared memory realm does not exist has looked up several solutions online to address oracle home and sid issues, or to have Net Configuration Assistant rebuild the local network service name. After practice, it does not work.
After summary, it is better to use the following methods to solve the problem:
1. First, let's take a look at ORADIM under ORACLE_BASE \ ORACLE_HOME \ DATABASE. LOG File E: \ app \ psun \ product \ 11.2.0 \ dbhome_1 \ database: the following error is reported only when you view the LOG !! Www.2cto.com ORA-00119: invalid specification for system parameter LOCAL_LISTENERORA-00132: syntax error or unresolved network name 'listener _ ORCL'

2. The error was found to be tnsnames. the following statement is missing in the ora file: LISTENER_MAXIMO = (ADDRESS = (PROTOCOL = TCP) (HOST = localhost) (PORT = 1521), restart the database instance service, restart the listener:

Use SQLPLUS and plsql to connect again. Okay!
Author: xiaocha2008